Breeding rye by continuous selection
1938
Sprague, H.B.
Rye is apparently partly cross-pollinated to the extent of approximately 50%, judging by the amount of xenia evident in a colorless kerneled variety of rye growing adjacent to a colored kerneled variety. Less than 10% of the foreign pollen was effective at a distance of 10 feet under comparatively normal conditions. A total of 216 strains were selected from a mass variety containing 10 varieties and strains after two years of natural crossing. Each of the 216 lines was continued from 1928 through 1937 by selection of superior plants in space-planted rows with open-pollination permitted between all lines in the breeding nursery. Parallel tests of yielding ability were made for all lines, using solid rows, with unselected common rye as the check. After five years of selection, 98 were chosen for 1933-34 on the basis of yield performance during the previous two years, and these were combined to form a new variety named Raritan. Raritan proved to be stable in yielding ability in subsequent generation, exceeding common rye by 10% to 12% in grain yield. Further improvement in productivity by continued selection within each of the 216 lines for the four years ending in 1937 is indicated by the yielding ability of the best 95 lines and by that of the entire breeding nursery. The limitations and advantages of this system of breeding are briefly discussed. Gradual concentration of desirable traits, and elimination of non-adaptive characters is provided without danger of losing valuable genes as usually occurs with inbreeding. The system requires relatively little time and skilled aid, but furnishes no information on inheritance of specific factors.
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